I think Seven of Nine would approach Tuvok like 'I am unaccustomed to being alone but the other crew members keep trying to socialise with me and I don't care for it. I've judged you the member of the crew least likely to engage in meaningless social interactions. I would like to spend some time with you.' And Tuvok is like 'that is logical. You may join me in my quarters this evening.'

She comes over and stands motionless by the wall while he sits and works on his reports and personal log. After 3 hours she's like 'that was satisfactory. I will join you again next week' and he's like 'acceptable'.

It's a major event in both of their social calendars.

eventually Tom Paris notices Seven coming and going from Tuvok’s quarters and goes to B'elenna like 'I think Tuvok and Seven are having an affair’ and she’s like 'Tom that’s ridiculous, it’s Tuvok. he’s the least likely person in the universe to have an affair. There’s no way.’ and he’s like 'no no I’m telling you they’re having an affair. you gotta talk to Seven woman on woman and get the dirt’ and she’s like 'ugh fine’

so she comes back to him like 'I spoke to Seven and she says she likes to spend time with Tuvok because he doesn’t try to make conversation’ and he’s like 'see they’re having an affair. no conversation straight to business.’ and B'elanna is like 'Seven literally never lies because she used to be a borg’ and he’s like 'okay well borg don’t have affairs either’ and she’s like 'what would it take to convince you that you’re wrong? hacking into the security feed of Tuvok’s quarters?’ and he’s like 'yes. let’s do that.’

so they hack into the security feed of Tuvok’s quarters and stand there watching the entire recording of Seven standing by the wall while Tuvok silently reads a book and afterwards Tom is like 'honestly? this is a lot weirder than if they were just having an affair and I’m very uncomfortable.’